The present invention pertains to the field of antenna systems including, more particularly, to embedded antenna systems.
Radio transceiver circuitry for use with a local wireless loop or other type of radio frequency broadcast and receiving application, typically generates significant noise or electromagnetic interference (EMI). This interference can affect the reception or transmission quality, can lead to a weakened signal, can result in the unneeded use of power and can interfere with other radio receivers. To compensate for this problem, transceiver units are typically enclosed by a metallic casing. Metallic casings provide a way to shield the antenna system from the unwanted electromagnetic interference generated by the electronics. In modern mass production applications, a metallic casing of this type can become a significant portion of the overall production cost. As with any manufactured good, there is a desire to minimize production costs as well as the other costs associated with producing and distributing radio transceivers.
As a necessary part of their functionality, radio transceivers require an antenna system to effectively receive and transmit the signals to be processed. In known transceivers, the antenna system is often composed of a separate stand alone unit. U.S. Pat. No. 5,093,670 describes such a stand alone antenna structure for use in a wireless communication system. The antenna is distinct from the transceiver enclosure, either mounted directly to the enclosure or somewhere proximate to the enclosure. In this type of antenna application, there is a need for an electrical connection from the antenna components to the electronics housed within the enclosure. Most commonly, this connection is in the form of a detachable coaxial cable. Besides the cost of these cable connectors, the larger the distance the antenna is from the electronics, the longer the cable and the larger the cost of installation and manufacture. Additionally, signal strength is lost within longer cables, reducing the sensitivity of the receiver and requiring a transmitter with more power.
U.S. Pat. No. 4,894,663 describes a radio housing where a loop antenna is molded or embedded into the housing. The antenna functions independently from the housing and is applied in a separate assembly step. The housing itself does not form an active component of the loop antenna.
U.S. Pat. No. 5,694,135 describes a connector for use in a patch antenna system. The connector is an independent element which co-axially connects to two separate conductive materials on the patch antenna. However, the described connector still requires an additional link to the operating electronics being used with the antenna.
Each of the separate components of these known transceivers described above (the enclosure, the antenna, the cable, a connection device, mounting hardware for the antenna) not only require additional manufacturing steps, they all contribute to extra cost, space allocation and maintenance problems. Each of these additional components can also contribute to a lower radio sensitivity and poorer performance.
With the modern trend in telecommunications moving toward the wireless communications arena and everyday consumers beginning to become increasingly involved with the use of wireless systems, the use of these transceiver stations is becoming more and more widespread. It thus becomes even more desirable to seek cost and space reductions wherever possible in the production of wireless transceiver stations.
Known patch antenna systems include three main components: a metallic region or radiating element forming the active area of the antenna, a metallic groundplane region, and a dielectric region sandwiched between the groundplane region and the radiating element. In a typical patch antenna system, all of these individual components are incorporated into a separate antenna structure and are often contained in a non-metallic enclosure to provide environmental protection and to facilitate mounting on a wall, roof, tower and/or mast.
The present invention comprises a radiating enclosure comprising a formed dielectric material sandwiched between formed conductive materials. The radiating enclosure is preferably directly connected to transceiver circuitry mounted within the enclosure through an integrated connection device.
In one aspect of the present invention, the radiating enclosure comprises a dielectric housing with an interior surface and an exterior surface, at least one radiating element attached to the exterior surface of the housing, and a groundplane material distributed on the interior surface of the dielectric housing. The radiating enclosure also preferably includes a connection device. The connection device preferably connects the radiating enclosure to the transceiver system through a controlled impedance interface.
In another aspect, the present invention also includes a method for manufacturing a radiating enclosure comprising forming a housing from a dielectric material, applying a groundplane material to the interior surface of the housing and attaching a radiating element to the exterior surface of the housing.